Absorbent sponges

ABSTRACT

A bonded, self-sustaining, single-use, disposable absorbent product having excellent softness and excellent strength, bulk, resilience and resistance to surface abrasion and linting, particularly when wet, comprising a plurality of layers of reinforced nonwoven textile fabrics, each of said layers comprising a synthetic polymeric thermoplastic reinforcing reticulate grid netting covered on each side by at least one layer of overlapping, intersecting fibers mechanically intertwined around and bonded to the individual elements of said grid netting, said plurality of layers of reinforced nonwoven textile fabrics being secured together at their peripheral edges to form a bonded, self-sustaining, single-use, disposable absorbent product, having excellent softness and excellent strength, bulk, resilience and resistance to surface abrasion and linting particularly when wet.

United States Patent Brooks et al.

[54] ABSORBENT SPONGES [72] Inventors: Berry A. Brooks, 284 EnglishCourt, Somerville, NJ. 08876; Norman R. Eisdorfer, 14 Colburn Rd., EastBrunswick, NJ. 08816 [22] Filed: Aug. 17, 1970 [21] Appl. No: 64,455

[52] US. Cl. ..128/296, 128/156, 161/160 [51] Int. Cl. ..A61f 13/00 [58]Field of Search ..l28/l32, 156, 290, 296; 161/160-161 [56] ReferencesCited UNITED STATES PATENTS 2,705,692 4/1955 Petterson 128/290 W2,833,283 5/1958 Spahr et a1 ..128/290 W 2,902,037 9/1959 Harwood et al..128/290 W 2,986,780 6/1961 Bletzinger ..128/290 W 3,047,444 7/1962l-larwood ..128/290 W 3,063,454 11/1962 Coates et a1. ..l28/290 W3,482,567 12/1969 Franklin ..128/132 D [151 3,683,921 [451 Aug. 15,1972

Atzorney--Alexander T. Kardos and Robert L. Minier [5 7] ABSTRACT Abonded, self-sustaining, single-use, disposable absorbent product havingexcellent softness and excellent strength, bulk, resilience andresistance to surface abrasion and linting, particularly when wet,comprising a plurality of layers of reinforced nonwoven textile fabrics,each of said layers comprising a synthetic polymeric thermoplasticreinforcing reticulate grid netting covered on each side by at least onelayer of overlapping, intersecting fibers mechanically intertwinedaround and bonded to the individual elements of said grid netting, saidplurality of layers of reinforced nonwoven textile fabrics being securedtogether at their peripheral edges to form a bonded, self-sustaining,single-use, disposable absorbent product, having excellent softness andexcellent strength, bulk, resilience and resistance to surface abrasionand linting particularly when wet.

5 Claims, 9 Drawing Figures Patented Aug. 15, 1972 3,683,921

4 Sheets-Sheet 75 ATTORNEY Patented Aug. 15, 1972 3,683,921

4 Sheets-Sheet 4 ABSORBENT SPONGES Thepresent invention relates toabsorbent products for absorbing and retaining body fluids, blood, andother body exudates. More particularly, the present invention relates toabsorbent products, such as surgical are equally applicable to otherabsorbent products wherein the properties of softness, strength, bulk,resilience, and resistance to surface abrasion and linting, particularlywhen wet, are of interest. Such other absorbent products include, forexample, general use sponges and pads, diapers, surgical dressings,postoperative dressings, underpads, combine pads, compresses, and thelike.

A laparotomy is a medical or surgical procedure or operation involvingan incision through any part of the abdominal wall into the abdominalcavity. During such a medical procedure, and in many other medicalprocedures and operations, such as open heart, thoracic, GYN, etc.,laparotomy sponges are used to absorb relatively large amounts of bodyfluids, blood, and other body exudates. Such laparotomy sponges are alsoused to Wall off organs, cover the outer edges of the incision, handleorgans, pack off areas in the inci sion opening so that itis easier togain access to other organs in the cavityopening, etc.

At the present time, sponges made of cotton gauze are customarily usedto carry out such functions. Such cotton gauze sponges are usually madefrom 4 plies of USP. 28 X 24 mesh cotton gauze and usually come in sizesof 12 inches X 12 inches square, 18 inches X 18 inches square, 18 inchesX 4 inches oblong, 36 inches X 8 inches oblong, etc.

Such cotton gauze sponges, however, are subject to many disadvantages.For example, they have a relatively high initial cost and haverelatively high subsequent I labor costs due to their re-usable naturerequiring laundering and sterilization after each use, hand removal ofpills or neps from the surface to prevent them from falling off duringan operation, repairing, resewing, hand-folding, etc. Also, the dangerof infection and cross-contamination is a very serious consideration.

Additionally, the used sponges, even though thoroughly washed andsterilized, are usually spotted with blood or other stains from previousmedical or surgical procedures or operations and thereby present a veryunsightly and somewhat repulsive appearance. The esthetic andpsychological effect of such a stained or spotted sponge is not verypleasing.

It is therefore very desirable that an economical, sin gle-use,disposable sponge or pad be developed and used to avoid theabove-mentioned disadvantages. It is also very necessary that such asponge or pad be soft and that it possess excellent strength, bulk,resilience, and resistance to surface abrasion and linting, particularlywhen wet.

It has been discovered that such a single-use, disposable sponge or'padmay be made by forming a synthetic polymeric thermoplastic reinforcinggrid netting defining a pattern of open areas, placing at least onelayer of absorbent fibrous materials on each side of the grid netting,adhering the layer of fibrous materials to the grid netting, thenforming a laminate of a plurality of layers of such grid netting andfibrous materials adhered thereto, and securing the plurality of layerstogether at their peripheral edges, and internally of such edges, if sodesired.

The inventive concept will be described in greater specificity byreference to the accompanying drawings and following specificationwherein there is illustrated and described preferred apparatus andmethods for producing the novel products of the present invention. Itmust be understood, however, that the inventive concept is not to beconsidered limited to the constructions shown except as determined bythe scope of the ap pended claims.

In the drawings:

FIG. 1 is a simplified, schematic, perspective, exploded view of areinforced nonwoven textile fabric composed of a plurality of fibrouswebs and a centrally located reinforcing reticulate grid netting, priorto assembling and processing in accordance with the principles of thepresent invention;

FIG. 2 is a fragmentary, perspective view of a preferred embodiment ofthe reinforcing reticulate grid netting of FIG. I;

FIG. 3 is a simplified, schematic drawing of a preferred embodiment ofapparatus and a method suitable for utilizing the principles of thepresent invention for making the reinforced nonwoven textile fabric suchas shown in FIG. 1;

FIG. 4 is a simplified, schematic drawing of a preferred embodiment ofapparatus and a method suitable for utilizing the principles of thepresent invention for assembling a plurality of reinforced nonwoventextile fabrics such as shown in FIG. 1;

FIG. Sis a simplified, schematic drawing of another preferred embodimentof apparatus and a method for utilizing the principles of the presentinvention for assembling a plurality of reinforced nonwoven textilefabrics such as shown in FIG. 1;

FIG. 6 is a simplified plan view of a laparotomy sponge as prepared byutilizing the principles of the present invention;

FIG. 7 is a partially exploded, magnified cross-sectional view of thelaparotomy sponge of FIG. 6, taken on the line 7 7 thereof, in thedirection indicated by the arrows.

FIG. 8 is a simplified plan view of another laparotomy sponge asprepared by utilizing the principles of the present invention;

FIG. 9 is a partially exploded, magnified, cross-sectional view of thelaparotomy sponge of FIG. 8, taken on the line 9-9 thereof, in thedirection indicated by the arrows.

With reference to the drawings and with particular reference to FIG. 1thereof, there is shown a reinforced nonwoven textile fabric 10comprising an outer layer- 12 of fibrous material, a centrally orinternally disposed reinforcing reticulate plastic grid netting l4, andanother outer layer 18 of fibrous material.

THE FIBROUS LAYER Each outer layer 12 and 18 may comprise merely asingle fibrous web or may comprise a number of laminated fibrous webswhich are brought together, usually to create a heavier weight layer.

The fibers which are employed to make up the layers 12 and 18 are highlyabsorbent and are preferably of a cellulosic nature, such as cotton orrayon. However, other fibers, either synthetic, man-made, or natural,may be used in various proportions for special purposes or for specialeffects. Illustrative of such other fibers are the polyamides (nylon6/6, nylon 6, nylon 610, nylon l 1, etc.), acrylic fibers (Acrilan,Creslan, Orlon, etc.), modacrylic fibers (Dynel, Verel, etc.), polyesterfibers (Dacron, Kodel, etc.), polyolefinic fibers (polyethylene,polypropylene, etc.), cellulose ester fibers (cellulose acetate,cellulose triacetate, etc.

It is not essential that the fibrous layers 12, 18 placed on each sideof the plastic grid netting 14 be composed of the same type of fiber orthe same denier or even that one layer be made of only one type of fiberor that both layers have the same weight. Blends and mixtures of theabove referred to fibers are, of course, possible in substantially anyrange of proportions or weights, as desired or required.

It is preferred that the fibers be of textile staple length orequivalent length, or at least be cardable, that is to say, they shouldbe from about one-half inch in average length up to about 3 inches ormore in average length. Shorter fibers, down to about three-sixteenthsinch or less in average length may be added in various proportions tocomprise up to about 50 percent by weight of the web, or may comprisethe entire web, particularly where the original method of web formationinvolved a fluid deposition of fibers, such as in a conventional ormodified aqueous papermaking process, or in air deposition techniques Insuch fluid deposition processes, average fiber lengths of aboutthree-six teenths inch or one-eighth inch are preferred to the extremelyshort fiber lengths of down to about one-sixteenth or one thirty-secondinch and even below, such as used in conventional papermaking processesfor making paper. Such very short fibers, such as these found inconventional papermaking processing, are of use, however, particularlyfor economic reasons or in those uses and applications wherein thetendencies toward paper-like properties and characteristics of paper andpaper products are not objectionable.

The denier of the synthetic or man-made fibers used in forming thefibrous webs is preferably in the range of the approximate thickness ofthe natural fibers mentioned and consequently deniers in the range offrom about 1 to about 3 are preferred. However, where greater opacity orgreater covering power is desired, deniers of down to aboutthree-fourths or even about onehalf may be employed. Where desired,deniers of up to l0, 15 or higher, may be used. The minimum and maximumdenier are, of course, dictated by the desires or requirements forproducing a particular fibrous web or nonwoven fabric, and by themachines and methods for producing the same.

The weight of the individual fibrous layer which is placed on each sideof the reinforcing reticulate grid netting may be varied withinrelatively wide limits, depending upon the requirements of the finishedproduct. A single, thin web of fibers, such as produced by a card,

may have a weight of from about 40 to about 200 grains per square yard.The minimum weight of one individual fibrous layer contemplated by thepresent invention is, however, about grains per square yard, usually obtained from one card or by plying two card webs. The maximum weight forone individual fibrous layer may range upwards to about 600 or moregrains per square yard depending upon the intended use of the finalproduct. Within the more commercial aspects of the present invention,however, individual fibrous layer weights of from about grains persquare yard to about 300 grains per square yard are contemplated.

These weights are measured prior to any shrinking of the fabric duringsubsequent processing and will increase accordingly subsequent to suchshrinking.

The number of fibrous layers in the reinforced nonwoven fabric should,of course, be at least two, that is, one layer on each side of theplastic grid netting, in order to obtain the desired or requiredeffects. Three, four, five or more layers, in any desired arrangementmay be used with the plastic grid netting in the center or closer to onesurface, as desired, where special effects are desired.

It is possible that a particular bonded reinforced nonwoven fabric maycomprise more than one reinforcing reticulate plastic grid netting. Forexample, the reinforced nonwoven fabric may comprise three layers offibrous webs as the two outermost layers and a central layer, with thetwo plastic grid nettings sandwiched in alternating fashion between thethree layers of fibrous webs. Other arrangements and otherconfigurations involving a plurality of plastic grid nettings and aplurality of fibrous webs are also possible depending upon the needs andrequirements of the particular situation.

Also, if carded or fiber oriented webs are used as the fibrous webs, itis not essential that the predominant direction of fiber orientation bethe same for all the card webs. If desired, the card webs may becross-laid with their predominant direction of fiber orientation atright angles or other angles to each other, whereby various strengthrelationships are available.

it is, of course, possible to apply a fibrous layer to merely one sideof the plastic grid netting and such would yield a fabric with differentproperties, characteristics, and appearance on each side. Such a fabricis of use where such differences can be tolerated.

THE GRID NETI'ING The reticulate grid netting 14 which is positionedbetween the fibrous layers 12 and 18 is a thermoplastic syntheticpolymeric material, such'as polypropylene, polyethylene (low density0.91-0.94, medium density 0.94, and high density 0.95-0.96 and above);polyamides especially nylon 66 (hexamethylene diamineadipic acid); nylon610 (hexamethylene diaminesebacic acid) and nylon 6 (polycaprolactam);polyesters, especially polyethylene glycol terephtholate; polyacrylicsor modacrylics; etc. These and other materials are of use provided theypossess the necessary thermoplastic properties and other chemical andphysical characteristics to the required degree and are capable ofthermal or other activation as described herein.

High density polyethylene having a density generally greater than 0.94grams per cubic centimeter, as well as predominantly isotacticpolypropylene are of exceptional applicability to the principles of thepresent inventive concept.

As shown in FIG. 2, the reticulate grid netting 14 comprisesintersecting rods or monofilaments 15 running in one direction and rodsor monofilaments 15a running cross-wise to the rods or monofilaments 15.The intersecting rods or monofilaments l5 and 150 are preferablybasically integral at their intersections l6 and define a regularpattern comprising a plurality of rectangular open areas 17therebetween. Methods and apparatus for making such reticulate gridnettings are disclosed in greater detail in copending, commonly assignedpatent applications Ser. No. 736,356, filed July 12, 1968; Ser. No.799,438, filed Feb. 14, 1969; Ser. No. 857,989,filed Sept. 15, 1969.

The open areas 17 are preferably rectangular or square, as shown, but itis to be appreciated that other geometric shapes may be used. Such othershapes include diamonds, parallelograrns, rhomboids, polygons, etc., andare created by having the rods or monofilaments 15 and 15a intersecteach other at acute or obtuse angles, other than the 90 angle shown.

The length of the sides of these geometric figures in the grid nettingmay vary relatively widely depending upon the needs and the requirementsof the particular situation. Sides as small as about one-twelfth inch orabout one-eighth inch are of use, although sides having a length ofabout one-fifth inch to about one-quarter inch are more commonlyemployed. Longer sides of up to about one-half inch or aboutthree-quarter inch are utilizable, and even longer lengths are useful inspecial situations.

The grid netting is usually described in terms of its mesh size. Forexample, a 3 X 5 grid netting means that there are three monofilamentsper inch in one direction and five monofilaments per inch in the otherdirection. Many other mesh sizes are of use. Such include: 4 X 9;4X4;7X9;etc.

The physical nature and the chemical composition of the grid netting 14,however, must be such that it possesses a sufficient degree of potentialtherrnoplasticity and potential shrinkability at the time it is insertedbetween the layers of fibrous materials.

Another important feature of the grid netting 14 is more grains persquare yard are found satisfactory. Within the more commercial aspectsof the present invention, however, a range of from about grains per'square yard to about 80 grains per square yard is deemed desirable.

The physical nature and the chemical composition of the grid netting 14,however, is such that it possesses a sufficient degree of potentialresidual shrinkage at the time it is inserted between the layers offibrous materials. Potential shrinkages of only about 3 percent are ofuse in the application of the present invention but larger potentialshrinkages are preferred in the range of from about 5 percent to about1.0 percent or l5 percent. Larger potential shrinkages up to 20 percentor 25 percent or even larger are useful in special applications.

The degree of residual or potential shrinkage which exists in the gridnetting is controlled to a large extent by the particular processing andmanufacturing techniques used in the original formation andpre-treatment of the grid netting itself. This is a very importantfactor. For example, the greater the degree of elongation, stretching,and drawing of the polymeric material during its original manufactureand the resulting greater degree of molecular orientation created in thepolymeric material, then the greater is the tendency of the polymericmaterial to return or shrink in the the fact that the thicknesses of theintersections of the filaments l5 and 15a can be made the same as thethicknesses of the interstitial filaments between'the intersectionswhereby there are no high spots or low spots as is present in aconventionally woven gauze or scrim in which the intersections of thewarp and filling are considerably thicker than the individualthicknesses of the interstitial warp and filling between theintersections. This flatness feature is, of course, a great advantage inthe manufacture of the laparotomy sponge in that there is more intimateand more complete contact of all parts of the grid netting with theadjacent fibrous webs. Additionally, there is a complete absence of highspots or bumbs in the laparotomy sponge which is advantageous during itssubsequent use in a medical or surgical procedure or operation.

The weight of the plastic grid netting may vary relatively widelydepending upon the needs and requirements of the particular situation.Weights as low as about 15 grains per square yard up to about 150 ormaterial to shrink is recognized in the art and such recognition leadsto the second factor affecting the shrinkage characteristics of thepolymeric material.

The second factor exists in the extent and in the duration of theannealing and relaxing treatment which is used to stabilize or heat-setthe grid netting subsequent to its original formation. Use of extensiveannealing or other heat-setting treatments such as normally usedpreviously in theart with such products will generally tend toreduce'the tendency of the formed grid netting to shrink whereby itsshrinkage capability substantially disappears. On the other hand, theuse of less extensive annealing or heat stabilizing treatments or thecomplete ommission thereof will serve to maintain the tendency of thegrid netting to shrink after formation whereby it is rendered suitablefor the purpose of the present invention.

A third factor in the development of the shrinkage properties lies inthe subsequent treatment of the laminated fabric'containing the gridnetting having the residual or potential shrinkage characteristics. ifsuch a laminated fabric is bonded and is then exposed to a heattreatment, such as a drying or resin-curing treatment at elevatedtemperatures and the grid netting is maintained in a tensionedcondition, then the shrinkage characteristics are usually unable toassert themselves and substantially no shrinkage takes place. However,if the heat treatment takes place under controlled tension conditions,such as the passage of the laminated fabric over heated drying canswhich rotate with controlled, predetermined progressively decreasingsurface speeds, then the shrinkage'characteristics can be asserted andthegrid netting will shrink.

Such shrinkage properties and characteristics are of great advantage incontrolling the thickness and bulk of the final product as well as thedegree of rippling or puckering which can be imparted thereto. Suchcontrolled rippling and puckering may be brought about at any desiredtime but preferably takes place during the heat sterilization of theabsorbent product prior to use. As a result of such shrinking, ripplingand puckering, the bulk or thickness is increased, and the softness andsurface interest are enhanced.

The extent of the increase in bulk or thickness, softness and surfaceinterest, etc., depends, of course, to a large extent upon thedifferential in shrinkage properties between the thermoplastic gridnetting and the fibrous webs which are adhered thereto. Inasmuch as theperipheral edges of the thermoplastic grid netting and the fibrous websare autogenously bonded together, and inasmuch as the thermoplastic gridnetting shrinks to a far greater degree than the fibrous webs adheredthereto, the puckering and rippling in the central area bounded by theperipheral edges will be greater when the difference in shrinkageproperties and characteristics is greater.

THE MANUFACTURE OF THE REINFORCED NONWOVEN FABRIC In FIG. 3, there isshown apreferred embodiment of a method and apparatus suitable forassembling an outer fibrous layer 22, a reinforcing reticulate plasticgrid netting 24, and another outer fibrous layer 28 to form a reinforcednonwoven fabric Pressure-applying rotatable rolls 29, 30 and 31, 32operate to press the various layers together into a laminated structure33. This laminated structure 33 is then passed through a conventionalfluid-rearranging apparatus 36 so as to rearrange the individual fibersthereof into a KEYBAK bundled non-woven textile fabric possessing apredetermined pattern of fabric openings and fiber bundles. Suchapparatusis described ingreater detail in U. Pat. No. 2,862,251 whichissued to Frank Kalwaites on Dec. 2, 1958 and reference thereto,particularly to FIGS. 7-10 thereof, is incorporated herein.

The rearrangement of the fibers during such a KEYBAK bundling process isparticularly advantageous in that the individual fibers of the fibrouslayers are rearranged and moved about sufiiciently so that they becomemechanically intertwined and wrapped around the individual rods orfilaments of the plastic grid netting. Such mechanical adherence of thefibrous layers to the grid netting is particularly advantageous in thecase of those polymeric grid materials which are more difficult toadhesively bond to the fibrous layers.

The rearranged laminated structure 33' is then passed throughconventional adhesive-applying or bonding apparatus 34 wherein a bondingagent is applied. The specific form of bonding method and apparatus isnot critical and basically any well known form of rotatable print rollswhich are suitably engraved or embossed as to pick up the proper amountof bonding agent from a trough or tank and deposit the same in thedesired pattern on the laminated fabric is suitable.

Other forms of bonding, using other forms of coating and impregnatingmethods and apparatus, are also possible. Spraying, padding, dipping,and other forms of saturation or overall bonding are of value.

The binder used in adhering the plurality of webs and the grid nettingtogether may be selected from a large group of such binders known toindustry. It is necessary, however, that a binder be used which cansatisfactorily adhere to and bond the different types of fibers togetheror at least mechanically interlock the fibers together. Representativeof the binders available for such a purpose are: regenerated cellulose;vinyl resins such as plasticized or unplasticized polyvinyl acetate,polyvinyl chloride, polyvinyl alcohol, etc., either as homopolymers orcopolymers; acrylic resins such as ethyl acrylate, methyl methacrylate,butyl acrylate, butyl methacrylate, etc.; butadiene resins such asbutadiene-acrylonitrile, butadiene-styrene, etc.; other syntheticrubbers; natural rubber; urea resins such as urea-formaldehyde, cyclicurea-formaldehyde, etc.; aldehyde resins such as melamine-formaldehyde,phenolformaldehyde, resorcinol-formaldehyde, etc.; epoxy resins;cellulose derivatives such as carboxymethyl cellulose; hydroxyethylcellulose, etc.; starches; gums; casein; etc.

These binders may be added, as desired, in the form of emulsions,solutions, dispersions, plastisols, powders, etc. Autogenic bondingpreferably by heat and/or pressure and/or solvents, may also be usedwhen thermoplastic fibers are present.

The percent add-on of such binder materials may be varied withinrelatively wide limits, depending to a large extent upon the specificbinder employed and upon the type, weight and thickness of the fibrousweb. For some binders, as low as about 1 percent by weight up to about12 percent by weight, based on the weight of the dry webs being bonded,has been found satisfactory. For other binders, as high as from about 15to about 50 percent by weight has been found preferable. Within the morecommercial aspects of the present invention, however, from about 2 toabout 35 percent by weight based on the weight of the dry webs beingbonded has been found desirable.

The particular size, shape and configuration of the binder pattern usedfalls within the scope and range of binder areas previously used in theprior art. Examples of some of these binder patterns may be found in theabovementioned U. S. Pat. Nos. 2,705,687 and 2,705,688 or in U. S.Pat.'No. 2,880,111. Specific examples of binder areas, binder shapes andsizes, and interbinder spaces are noted in said patents.

The rearranged laminated structure 33" with the applied binder is thenforwarded to a suitable heating device such as a heated oven 35 which ismaintained at an elevated temperature in order to dry and, if necessary,cure the applied binder.

The temperature, pressure and duration of time of the heating, dryingand curing are, of course, interdependent. Higher'temperatures permitthe use of shorter exposure times, and lower temperatures require theuse of longer exposure times. Temperatures in the range of from about212 to about 325 F. are normally used with exposure times of from about20 seconds to about 30 minutes.

The combined mechanical and adhesive bonding between the fibrous websand the plastic grid netting thus forms a superior bond to that obtainedby mechanical bonding alone or by adhesive bonding alone.

The bonded nonwoven fabric 10' is then forwarded to suitable wind-uprolls 37 to be used as supply rolls for the next procedure.

THE MANUFACTURE OF THE ABSORBENT PRODUCT under a heated cutting andheat-sealing platen 42 which reciprocates vertically, as shown, andserves to heat-seal the laminate 39 into a bonded, self-sustainingabsorbent product.

The temperature, pressure, and duration of time of the heat-sealing are,of course, interdependent. Higher temperatures permit the use of shorterexposure times and lower pressures, and lower temperatures require theuse of longer exposure times and higher pressures. Temperatures in therange of from about 225 to about 400 F. or 600 F., for periods of a partof a second, say 0.2 second, or a few seconds, say 1 or 2, up to orseconds, are possible. The pressures employed are generally in the rangeof from about 30 pounds per square inch (gauge) to about 100 pounds persquare inch (gauge) and preferably from about 40 pounds per square inchto about 80 pounds per square inch (gauge).

As will be described in greater detail hereinafter, the heat sealingtakes place along the peripheral edges of the laminate 39 as well asinternally thereof, as desired or required. Pressure is exerted by theheated platen 42 which presses the laminate 39 against a stationary baseor anvil 44. At the rearward or trailing edge of the platen 42 and anvil44, a conventional cutting device (not shown) is used to cut the endlesslength of laminate 39 into shorter lengths 46 which are forwarded byconveying means such as a conveyor belt 48 to an assembly zone 50 wheretapes or loops 52 are applied, as desired or required.

Although four reinforced nonwoven fabrics are used to illustrate theinvention, it is to be appreciated that other combinations and othernumbers of reinforced nonwoven fabrics may be used.

In FIG. 5, there is shown a variation of the method and apparatusillustrated in FIG. 4. In FIG. 5, supply rolls 57 forward fourreinforced nonwoven fabrics through the nips of rotatablepressure-applying rolls 58, 60 to form a laminate 59. This laminate isthen passed through the nip of heated rotatable sealing and cuttingrolls 62 and 64 which serve to press together and heat the laminate atits peripheral edges and internally thereof, as desired or required.Conventional cutting means (not shown) are used to sever the endlesslengths of the laminate 59 into short lengths 66 which are forwarded byconveying means such as a conveyor belt 68 to an assembly zone 70 wheretapes of loops 72 are attached, as desired or required.

FIGS. 6 and 7 illustrate one typical form of bonding used to bond thelaminate 39 at its peripheral edges 51 and internally thereof. FIG. 6shows one manner of attaching the tapes or loops 52 to the main body ofthe laparotomy sponge.

FIGS. 8 and 9 illustrate another typical form of bond ing used to bondthe laminate 59 at its peripheral edges 71 and internally thereof. FIG.8 shows another manner of attaching the tapes or loops 72 to the mainbody of the laparotomy sponge.

It is to be appreciated that many other forms of bonding and bondingdesigns internally of the peripheral edges may be employed. For example,instead of using diagonals which form an X as in FIG. 8, lines parallelto the peripheral edges may be used to form a dividing the sponge intofour substantially equal quadrants. Instead of using rectangles as inFIG. 6, other geometric figures may be used. Such other figures includesquares, ellipses, ovals, circles, annuli, polygons, hexagons, etc.

The invention will be further described by reference to the followingExamples wherein there are disclosed preferred embodiments of thepresent invention. However, it is to be appreciated that such Examplesare illustrative and not limitative of the broader aspects of theinventive concept.

EXAMPLE I Four laparotomy sponges having dimensions of about 14 inches X14 inches (after sterilization) are prepared to the followingspecifications:

1. Four plies of bonded rearranged KEYBAK nonwoven fabric comprisingrayon fibers, 1% denier and l 9/ 16 inches staple length with each plycomprising two fibrous webs weighing about 172 grains per square yard toprovide a total weight (four plies) of 1,376 grains per square yard. Noreinforcement is used.

2. Four plies of reinforced bonded rearranged KEYBAK nonwoven fabricwith each ply comprising a polypropylene reinforcing re'ticulate grid 3X 5 netting weighing 45 grains per square yard covered on each side by afibrous web of rayon fibers 1%. denier and 1 9/ 16 inches staple length,each web weighing 185 grains per square yard to provide a weight of 414grains per square yard per ply or a total weight (four plies) of 1,656grains per square yard.

(3) Four plies of reinforced bonded rearranged KEYBAK nonwoven fabricwith each ply comprising a 6 X 4 rayon leno'weave weighing 71 grains persquare yard covered on each side by a fibrous web of rayon fibers 1%denier and 1 9/16 inches staple length, each web weighing 185 grains toprovide a weight of 440 grains per square yard per ply or a total weightof 1,760 grains per square yard.

(4) Four plies of reinforced bonded rearranged KEYBAK" nonwoven fabricwith each ply comprising a 6 X 6 rayon leno weave weighing 106 grainsper square yard covered on each side by a fibrous web of rayon fibers 1%denier and 1 9/16 inches staple length, each web weighing 185 grains persquare yard to provide a weight of 476 grains per square yard per ply ora total weight of 1,904 grains per square yard.

All the fibrous webs are bonded with a formulated Rohmgg Haas HA-8,which is essentially a self crosslinkable ethyl acrylate copolymerbinder. A wavy line print pattern is used with four 0.024 inch widelines per inch. There are apertures formed per square inch during thefluid-rearranging process. The general procedures of FIG. 3 arefollowed, when applicable to the type of sample being made.

The four samples are formed into laparotomy sponges in accordance withthe method illustrated in FIG. 4. They are sterilized to shrink andripple to varying degrees of surface interest, softness, bulk andrippled effect as a result of such sterilization.

Sample 2 containing the thermoplastic grid netting bonds autogenously atits peripheral edges and internally thereof as illustrated in FIGS. 6and 7. The thermoplastic grid netting softens and causes the bonding.Samples 1, 3 and 4, not containing any thermoplastic grid netting do notbond autogenously and are stitched and sewn together at their peripheraledges and internally thereof.

Three samples of each are prepared; all three are evaluated and theaverage evaluation is shown below:

nonwoven nonwoven IIOI'IWOVCI'I nonwoven fabric fabric fabric fabric w/grid w/ 6 X 4 w/ 6 X 6 control netting leno leno Grain weight per 344414 440 476 sq. yd. per ply v Total grain weight 1376 1656 1760 1904 per4 plies *Tensile Strength 18.6 21.3 29.4 28.6 M/D Dry (lbs.) *TensileStrength 11.8 16.6 15.5 16.6 M/D Wet (lbs.) *Tensile Strength 0.9 7.95.9 10.2 C/D Dry (lbs.) *Tensile Strength 0.8 7.5 3.9 6.4 CID Wet (lbs.)Bulk (1 ply) lbs. 0.012 0.014 0.014 0.017 Bulk 4 ply) lbs. 0.038 0.0530.049 0.057 Softness 4 X 4 10.2 16.2 34.5 31.5

*4-ply strips, l-inch width 1 Sample 1 (four plies of bonded nonwovenfabric without any reinforcement) is unsatisfactory. The cross tensilestrengths are too low; and the wet and dry bulk and resilience are toolow.

2. Sample 2 (4 plies of bonded nonwoven fabric with grid nettingreinforcement) is satisfactory. Tensile strengths are excellent; wet anddry bulk and resilience are good; and softness is excellent. Thepuckered, rippled effect creates desirable softness, bulk, and surfaceinterest.

3. Sample 3 (four plies of bonded nonwoven fabric with 6 X 4 leno weavereinforcement) is unsatisfactory. Softness is too low; wet and dryresilience are too low; and fabric is too harsh and has anunsatisfactory hand.

4. Sample 4 (four plies of bonded nonwoven fabric with 6 X 6 leno weavereinforcement) is unsatisfactory. Softness is too low; wet and dryresilience are too low; and fabric is too harsh and has anunsatisfactory hand.

EXAMPLE II The procedures of Example 1 are followed substantially as setforth therein with the exception that the HA-8 ethyl acrylate polymerbinder is replaced with a viscose regenerated cellulose binder. Allother conditions remain the same.

The test results are comparable to those obtained in Example I. Only thesecond sample (four plies of bonded nonwoven fabric with a grid nettingreinforcement) is completely satisfactory.

EXAMPLE Ill The procedures of Example 1 are followed substan tially asset forth therein with the exception that the PIA-8 ethyl acrylatepolymer binder is replaced by a Goodrich 2600Xl20 self cross-linkable.acrylic copolymer binder. All other conditions remain the same.

The test results are comparable to those obtained in Example 1. Only thesecond sample (four plies of bonded nonwoven fabric with a grid nettingreinforcement) is completely satisfactory.

EXAMPLE IV The procedures of Example I are followed substantially as setforth therein with the exception that there are (a) apertures, (b) 225apertures, and (c) 144 apertures formed per square inch rather thanapertures during the fluid-rearranging process. The 144 and 225apertured designs are square designs; that is, the apertures are alignedin rows in two directions in checkerboard fashion. The 95 and 165apertured designs have the apertures staggered or nesting into eachother in adjacent rows.

The test results are comparable to those obtained in Example I. Only thesecond sample (four plies of bonded nonwoven fabric with a grid nettingreinforce ment) is completely satisfactory.

EXAMPLE V The procedures of Example I are followed substantially as setforth therein with the exception that in Sample 2, the 3 X 5polypropylene reinforcing reticulate grid netting weighs: (a) 39 grainsper square yard; (b) 47 grains per square yard; and (c) 55 grains persquare yard rather than 45 grains per square yard.

The results are generally comparable to those obtained for Sample 2 inExample I, with the additional observation that autogenic bonding iseasier and more effective with larger amounts of the thermoplasticpolypropylene grid netting.

EXAMPLE VI The procedures of Example I are followed substantially as setforth therein with the exception that in Sample 2 the reinforcingreticulate grid netting is (a) predominantly 'isotactic polypropyleneand (b) high density polyethylene having a density between 0.95 and 0.96grams per cubic centimeter.

The results are generally comparable to those obtained for Sample 2 inExample 1. Both products are satisfactory for use as laparotomy sponges.

EXAMPLE VII Six laparotomy sponges are prepared to the followingspecifications:

1 Four plies of bonded rearranged KEYBAK nonwoven fabric comprisingrayon fibers, 196 denier and 1 9/16 inches staple length; each plycomprising two fibrous webs weighing about 172 grains per square yard toprovide a total weight (four plies) of 1,376 grains per square yard.

2 Four plies of reinforced bonded rearranged KEYBAK nonwoven fabric witheach ply comprising a polypropylene reinforcing reticulate 3 X 5 gridnetting weighing 45 grains per square yard covered on each side by afibrous web of rayon fibers 1% denier and 1 9/16 inches staple length,each web weighing 185 grains per square yard to provide a weight of 4 14 grains per square yard per ply or a total weight (four plies) of 1,656grains per square yard. i

3. Four plies of reinforced bonded rearranged KEYBAK" nonwoven fabricwith each ply comprising a 6 X 4 rayon leno weave weighing 71 grains persquare yard covered on each side by a fibrous web of rayon fibers 1%denier and 1 9/16 inches staple length, each web weighting 185 grains toprovide a weight of 440 grains per square yard per ply or a total weightof 1,760 grains per square yard.

4. Four plies of reinforced bonded rearranged KEYBAK nonwoven fabricwith each ply comprising a 6 X 6 rayon leno weave weighing. 106 grainsper square yard covered on each side by a fibrous web of rayon fibers 1%denier and 1 9/16 inches staple length, each web weighting 185 grains toprovide a weight of 476 grains per square yard per ply or a total weightof 1,904 grains per square yard.

5. Four plies of bonded MASSLINN nonwoven fabric which are notrearranged and not reinforced are made from rayon fibers 1% denier and 19/16 inches staple length; each ply comprises two fibrous webs eachweighing about 172 grains per square yard to provide a total weight(four plies) of 1,376 grains per square yard.

6. Four plies of U.S.P-. 28 X 24 cotton mesh gauze.

All the fibrous webs are bonded with a formulated Rohm & Haas HA-8,which is essentially a self crosslinkable ethyl acrylate copolymerbinder. A wavy line print pattern is used with four 0.024inch wide linesper inch. There are 165 apertures formed per square inch during thefluid-rearranging process. The general procedures of FIG. 3 arefollowed, when applicable to the type of sample being made.

The six samples are formed into laparotomy sponges in accordance withthe method illustrated in FIG. 4. They are sterilized by heating. OnlySample 2 shrinks and puckers to a desirable surface interest andappearance, and possesses excellent bulk and a pleasing rippled effectas a result of such sterilization and the differential shrinking effect.

Sample 2 containing the thermoplastic grid netting bonds autogenously atits peripheral edges and internally thereof, as illustrated in FIGS. 6and 7. Samples 1 and 3-6 which do not contain a thermoplastic gridnetting do not bond autogenously and are stitched and sewn together.

36 inch X 36 inch squares are cut from each sample and are autoclaved at250 F. for minutes. Each sample is then soaked in distilled water forthirty seconds and allowed to absorb 150ml. Excess water absorption isremoved by squeezing. Each sample is then placed in a 1,000 ml. tallPyrex beaker (4 inch internal diameter) in a randomlyballed manner. Aplastic beaker (3% inch external diameter) is placed on top on therandomly balled sample and various weights are added, causing the sampleto compress. The degree of compression is observed. All weights are thenremoved and the amount of spring-back or resilience is observed. Theresults are as follows:

63 l .5 1282.5 1941.5 Amount of grams grams grams spring-back Keybuknonwoven 730 800 820 30 fabric Nonwoven fabric 390 600 670 with gridnetting 450 630 700 I00 (3 samples) 450 650 700 I00 Nonwoven fabric 650740 800 40 with 6 X 4 leno Nonwoven fabric 600 750 770 60 with 6 X 6leno Masslinn nonwoven 670 760 820 i 50 fabric 28x24 cotton gauze 750800 820 40 The larger the number, the greater is the compaction. Valuesof 800 and 820 reveal substantially no resistance to the application ofcompressive force. Such EXAMPLE Vllll The procedures of Example V11 arefollowed substantially as set forth therein with the exception that (0.9percent) saline solution, containing sodium chloride in the proportionof nine to 1000, is substituted for the distilled water.

The results are comparable to those obtained in Example VII. Sample 2containing the thermoplastic grid netting passes the wet bulkcompression test and the resilience test. All other samples fail thesetests.

EXAMPLE 1X Six laparotomy sponges are prepared to the followingspecifications:

1. Four plies of bonded rearranged KEYBAK" nonwoven fabric comprisingrayon fibers, l k denier and 1 9/16 inches staple length; each plycomprising two fibrous webs weighing about 172 grains per square yard toprovide a total weight (four plies) of 1,376 grains per square yard.

2. Four plies of reinforced bonded rearranged KEYBAK" nonwoven fabric;polypropylene reinforcing reticulate 3 X 5 grid netting weighing 45grains per square yard covered on each side by a fibrous web of rayonfibers 1% denier and 1 9/16 inches staple length, each web weighinggrains per square yard to provide a weight of 414 grains per square yardper ply or a total weight (four plies) of 1,656 grains per square yard.

3. Four plies of reinforced bonded rearranged KEYBAK nonwoven fabric;polypropylene reinforc- 15 ing reticulate 4 X 9 grid netting weighing 55grains per square yard covered on each side by a fibrous web of rayonfibers 156 denier and 1 9/ 16 inches staple length, each web weighing185 grains to provide a weight of 425 grains per square yard per'ply ora total weight (four plies) of 1,700 grains per square yard.

4. Four plies of reinforced nonwoven fabric; 6 X 4 rayon leno weaveweighing 71 grains per square yard covered on each side by a fibrous webof rayon fibers 196 denier and 1 9/16 inches staple length, each webweighing 185 grains per square yard to provide a weight of 440 grainsper square yard per ply or a total weight of 1,760 grains per squareyard.

5. Four plies of reinforced bonded rearranged KEYBAK nonwoven fabric; 6X 6 rayon leno weave weighing 106 grains per square yard covered on eachside by a fibrous web of rayon fibers 1% denier and 1 9/16 inches staplelength, each web weighing 185 grains to provide a weight of 476 grainsper square yard per ply or a total weight of 1,904 grains per squareyard.

6. Four plies of USP. 28 X 24 cotton gauze fabric.

The linting properties and characteristics of these samples aredetermined as follows: 10 samples of each sponge are steam sterilized at250 F. for 30 minutes and then conditioned at 65 percent RelativeHumidity and 70 F. for at least 4 hours. The samples are then weighed.The samples are then immersed and dipped five times in 1,000 ml. salinesolutions in a 1,500 m1. beaker. The samples are squeezed once to removeall free running water which is returned to the 1,500 ml. beaker. Thewet samples are then placed on a black filter paper on a Buchner funneland the remainder of the collected 1,000 ml. saline solution filteredthrough the sample on the black filter paper. The samples are thenwashed with distilled water. The lint is then collected and weighed andaverages for the ten samples are calculated. The results are as follows:

Linting 1. Keybak nonwoven fabric 0.016% 2. Nonwoven fabric with 3 X 50.005% grid netting (3 samples) 0.005%

3. Nonwoven fabric with 4 X 9 0.005% grid netting 4. Nonwoven fabricwith 6 X 4 0.01 1% leno 5. Nonwoven fabric with 6 X 6 0.010% leno 6. 28X 24 cotton gauze 0.01 1% Samples 2 and 3 containing the reinforcingthermoplastic grid netting pass the linting test and are consideredsatisfactory. Samples 1 and 4-6 do not pass the linting test describedabove and are considered relatively unsatisfactory.

EXAMPLE X A reinforced bonded rearranged KEYBAK nonwoven fabric isprepared by placing a fibrous web of rayon fibers 1% denier and 1 9/16inches staple length weighing 750 grains per square yard on each side ofa polypropylene reinforcing reticulate 4 X 9 grid netting weighing 100grains per square yard. Rearrangement forms fabric openings and fiberbundles, whereby many individual fibers are intertwined and wrappedaround the grid netting. Adhesive bonding with I-IA-8, a selfcross-linkable ethyl acrylate copolymer, bonds the nonwoven fabric.Autogenic heat sealing at the peripheral edges and internally thereof isrendered more difficult due to the heavier weight of the fibrous webs.However, the heavier weight of the polypropylene grid netting helps inthe autogenic bonding. The resulting product, however, is relativelystiff and has poor drape and hand. It is not soft. Upon sterilization,the reinforced nonwoven fabric shrinks as doall such fabrics but theinstant fabric becomes stiff and boardy. It is not suitable for use as asurgical sponge or pad.

EXAMPLE XI Four samples as described in particularity in Example I areprepared and their bulk or thicknesses measured both before and afterundergoing sterilization procedures in steam at 250 F. for 30 minutes.The results are as follows:

Thicknexs Percent Before After Change 1. Keybak" nonwoven fabric 0.009"0.009" 0.0%

2. Keybak" nonwoven fabric 0.018" 0.020" +1 1.1%

with grid netting 0.020" 0.023" +l5.0%

(3 samples) 0.014" 0.018" +28.6%

3. Keybak nonwoven fabric 0.013" 0.014" +0.77% with 6 X 4 leno 4.Keybak" nonwoven fabric 0.017" 0.016" 0.59% with 6 X 6 leno Sample 2shrinks as noted and creates a very desirable rippling and puckeringeffect, thus enhancing the surface interest of the product andincreasing the softness and bulk thereof. These products are consideredsatisfactory for use as laparotomy sponges.

Samples 1, 3 and 4 do not shrink materially and remain relatively flatwithout any enhancement of the surface interest, softness or bulk. Theseproducts are not considered satisfactory for use as laparotomy sponges.

EXAMPLE XII A laparotomy sponge is formed of six plies of reinforced,bonded, rearranged KEYBAK nonwoven fabric, each ply comprising a centrallayer of polypropylene reinforcing reticulate grid 3 X 5 nettingweighing 40 grains per square yard, covered bn each side by a fibrousweb of rayon fibers 1% denier and 1 9/16 inches staple length, weighinggrains, for a total weight (six plies) of 1,920 grains per square yard.The laparotomy sponge is found satisfactory in use.

EXAMPLE XIII l7 specific Examples, such is for the purpose ofillustrating the invention and is not to be construed as limiting it,except as defined by the appended claims.

What is claimed is: 1. An improved sterilized surgical sponge comprisinga plurality of layers of reinforced, non-woven, textile fibers; saidlayers each comprising a synthetic, polymeric thermoplastic reinforcinggrid covered on each side by at least one layer of a non-woven textilefabric of overlapping, intersecting fibers mechanically intertwinedaround the individual elements of said grid; said grid having, prior tosterilization, a shrinkage potential of about 3 to about 25 percent;said plurality of reinforcedlayers being secured together continuouslyat their peripheral edges and intermittently interfrom aboutthree-sixteenths inch and to about 3 inches.

3. The sponge of claim 1 wherein the weight of each individual fibrouslayer ranges from about grains per square yard to about 600 grains persquare yard.

4. The sponge of claim 1 wherein the plurality of layers are securedtogether by heat binding.

5. The sponge of claim 1 wherein the thermoplastic reinforced grid ismade of polypropylene.

2. The sponge of claim 1 wherein the fibers of said non-woven textilefabric are of an average length of from about three-sixteenths inch andto about 3 inches.
 3. The sponge of claim 1 wherein the weight of eachindividual fibrous layer ranges from about 100 grains per square yard toabout 600 grains per square yard.
 4. The sponge of claim 1 wherein theplurality of layers are secured together by heat binding.
 5. The spongeof claim 1 wherein the thermoplastic reinforced grid is made ofpolypropylene.